I love gong to the Moonlight Cinema and I thought I'd post a link to the site so you can love it too! :
Basically, it's in the Botanic Park. It's normally easy enough to get a park (unless the zoo have a function on) and you can meet up with people, have a picnic /drinks and nibbles / buy food and drink there and relax as the sun goes down. When it's sufficiently dark - usually round 9pm- the film come on and you can snuggle up and watch the film whilst enjoying the warm, fresh air....and ignoring the possums!
You can take your own beanbag, or rent one there, or one of those beach seat-y things or even an ordinary chair but then I think you have to sit at the back. Remember it does get cold so rug up or I have seen people take a sleeping bag.
But, please, DON'T talk when the film is on!